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The coronavirus epidemic is a challenge for modern medicine. The high contagiousness of new variants of the coronavirus favors the rapid transmission of COVID-19. The leading Delta variant, however, is not the most infectious virus ever. What are the world’s most contagious viruses? How does the SARS-CoV-2 coronavirus compare to them and will the Omikron variant be at the forefront of the ranking?
- When assessing viral infectivity, the reproductive rate, also known as the R index, is used
- So far, measles has had the highest R rate in human history
- The chickenpox virus is also high in the ranking
- More information can be found on the Onet homepage
Why is the fight against viruses difficult?
Among pathogens, viruses, more specifically, have been the target for a long time koronawirus SARS-CoV-2. All because of the COVID-19 pandemic, which is persistent, disrupting social life, the economic situation and the state of public health. When the situation seems to stabilize, new virus strains emerge, and the mutations found in them make it difficult to quickly extinguish the epidemic.
Why is it so hard to win against viruses? Difficulties in the treatment of viral diseases result from the specificity of this type of pathogens. They are not susceptible to antibiotics, so the implementation of targeted therapy becomes possible only when an effective drug is found. Until then, symptomatic treatment is applied. Vaccines help to prevent viral diseases, but their invention can be troublesome and time-consuming – no vaccine has been developed for years, e.g. for HIV. In addition, viruses rapidly mutate, which could be observed in the case of the coronavirus and its variants Alpha, Beta, Gamma and Delta.
Zobacz: Mutation, variant, strain, variant of the coronavirus. Can these terms be used interchangeably?
Contagiousness is another issue affecting the effectiveness of virus transmission and transmission in society. Some viruses have the ability to spread to successive hosts extremely efficiently. One is the Coronavirus Delta variant, a a new strain of Omikron could prove even more contagious. How contagious is the SARS-CoV-2 coronavirus compared to other viruses that plague humanity?
How do we rate the contagiousness of viruses?
The R, or viral reproductive rate, is commonly used to assess the contagiousness of individual viruses. Another name for this parameter is base restore number. How to interpret the value of the R indicator? It is the average number of people who will become infected by one sick person. If the R value is 2, then the patient has the potential to infect two more people with the pathogen. The higher the reproductive rate of a virus, the more contagious it is.
Based on the R-factor, we can list the following pathogens among the most contagious viruses in history:
- virus measles: R with a value of 12-18;
- chickenpox virus: R with a value of 10-12;
- mumps virus: R value of 10-12;
- rubella virus: R with a value of 6-7;
- polio virus: R with a value of 5-7;
- smallpox virus: R with a value of 3,5-6,0;
- wirus HIV: R values of 2–5.
Check also: Seven most dangerous viruses in the world
It should be remembered that the R factor only informs us about how effectively a given virus can spread to other people. Other features of the individual viruses, such as the severity of the infection, mortality or complications, they can also influence the overall picture of a given disease and its individual or social consequences.
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What are the most contagious viruses ever?
The most contagious viral disease is measles. The measles virus is spread by airborne droplets and airborne viruses, and one person can infect 12 to 18 others. If they are not vaccinated or ill, they will develop measles with a 90-95% chance. Vaccines have significantly reduced the incidence of the disease. In the past, measles epidemics repeated every 2-3 years, in Poland alone, they led to the death of 200-300 children a year and serious post-sickness complications in thousands of others.
The chickenpox virus is high in the ranking, which can spread from an infected person to 10–12 others. The course of this disease is usually more severe in adults than in children, and complications may also appear in previously healthy people. A contagiousness similar to chickenpox (R value 10–12) is observed in mumps, a common parotitis. Although mumps is generally mild, it is considered to be the main trigger of viral meningitis in children.
Some viral diseases can cause severe complications.
Rubella virus has a slightly lower reproductive rate of the virus, with an R of 6-7. It is another disease that, before universal vaccination was introduced, caused epidemics that reappeared every few years.
Measles, chickenpox, mumps and rubella are diseases that have been significantly reduced in prevalence in countries with high vaccination coverage. As a result, despite their high contagiousness, they rarely cause epidemics.
A high rate of viral reproduction is also observed in polio, smallpox and HIV.
Also read: MMR vaccine – vaccination against measles, mumps and rubella [EXPLAINED]
Among the most contagious viruses in history, there are several coronaviruses, which, however, have a lower R-factor than measles, chickenpox, rubella and polio. One of them is SARS virus (R value 2-4) causing severe acute respiratory syndrome. The pathogen contributed to the epidemic of this disease at the turn of 2002 and 2003. During the epidemic, the SARS virus caused the disease of approx. 8 people. people around the world, and its mortality was close to 10 percent.
The MERS coronavirus (R value of 0,5), which attacked in 2012, is now much lower than the SARS virus. It has led to several epidemics so far, but these have occurred locally, leading to up to several hundred cases at a time. The MERS virus, however, has a high mortality rate of 35 percent.
But what about the coronavirus, which is the source of the global pandemic? In the case of COVID-19, contagiousness should be interpreted taking into account the individual strains of the virus. According to analyzes, the primary strain of the SARS-CoV-2 virus was contagious at a level of approximately R = 2,9. In the list of the most contagious viruses in history, however, two other variants of the SARS-CoV-2 coronavirus stand out:
- variant Alpha with an R coefficient of 4-5;
- Delta variant with an R coefficient of 5-8.
The Delta variant of the coronavirus has been the most contagious so far, ranging between polio (R-value 5-7) and rubella (R-value 6-7). For comparison with another common infectious disease – the R coefficient for the common cold is 2-3, and for the seasonal flu it is 1,3.
- You can buy a set of FFP2 filtering masks at an attractive price on medonetmarket
Czy wariant Omikron może być bardziej zaraźliwy od Delty?
The Delta variant is a highly contagious strain of the coronavirus. However, scientists are worried that the latest variant of the Omikron at the moment has mutated in such a way that its contagiousness may increase significantly. There were suspicions that Omikron would prove to be even more contagious than Delta.
Are the concerns justified? It is hard to say until the results of the current research on the Omikron variant will be released. However, the current evolution of the coronavirus cannot be ignored – the Delta variant has turned out to be twice as contagious as the original strain. Even if Omikron does not double its R value once again, there is a certain chance it will overtake Delta and even catch up with chickenpox or measles in the contagiousness ranking.
Also read:
- Omicron. The new Covid-19 variant has a name. Why is it important?
- What are the symptoms of the new Omikron variant? They are unusual
- COVID-19 has taken over Europe. Lockdown in two countries, restrictions in almost all [MAP]
- What are the symptoms of COVID-19 patients now?
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